public static void WriteDirective(
            this DocumentWriter writer,
            DirectiveNode node)
        {
            writer.Write('@');

            writer.WriteName(node.Name);

            if (node.Arguments.Any())
            {
                writer.Write('(');

                writer.WriteMany(node.Arguments, (n, w) => w.WriteArgument(n));

                writer.Write(')');
            }
        }
 public static void WriteNamedType(
     this DocumentWriter writer,
     NamedTypeNode node)
 {
     writer.WriteName(node.Name);
 }